Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538459
W. Whitney
Vacuum tubes have been subjects of research for years. Approximately three years ago scientists in General Electric Research Laboratories succeeded in constructing a radio tube having a wavelength of six meters and a frequency of 50,000,000 cycles per second, capable of radiating 10 to 15 kilowatts of energy. This is fifty times as much power as any short-wave tube previously had been able to produce.
{"title":"Short-wave high-power radio tube","authors":"W. Whitney","doi":"10.1109/JAIEE.1930.6538459","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538459","url":null,"abstract":"Vacuum tubes have been subjects of research for years. Approximately three years ago scientists in General Electric Research Laboratories succeeded in constructing a radio tube having a wavelength of six meters and a frequency of 50,000,000 cycles per second, capable of radiating 10 to 15 kilowatts of energy. This is fifty times as much power as any short-wave tube previously had been able to produce.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"250 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117026446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538466
H. S. Osborne
This paper outlines a comprehensive plan for improved switching of long haul toll telephone traffic in the United States and eastern Canada. A brief discussion is given of the methods of designing the toll plant to give adequate transmission efficiency for all connections established in accordance with this plan. This includes a new method of providing amplification at intermediate switching points replacing the cord circuit repeater method.
{"title":"Abridgment of a general switching plan for telephone toll service","authors":"H. S. Osborne","doi":"10.1109/JAIEE.1930.6538466","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538466","url":null,"abstract":"This paper outlines a comprehensive plan for improved switching of long haul toll telephone traffic in the United States and eastern Canada. A brief discussion is given of the methods of designing the toll plant to give adequate transmission efficiency for all connections established in accordance with this plan. This includes a new method of providing amplification at intermediate switching points replacing the cord circuit repeater method.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"115 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131806841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538468
F. D. Fielder, E. Beck
Rotating machines directly connected to overhead lines are subject to damage from lightning surges. Many methods of protection against such damage are possible and several of them are discussed in this paper. Laboratory experiments have been made to show the normal distribution under various steepnesses of waves, and the improvement of unsatisfactory distributions by means of condensers or lightning arresters connected to various parts of the windings has been studied.
{"title":"Abridgment of effects of lightning voltages on rotating machines and methods of protecting against them","authors":"F. D. Fielder, E. Beck","doi":"10.1109/JAIEE.1930.6538468","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538468","url":null,"abstract":"Rotating machines directly connected to overhead lines are subject to damage from lightning surges. Many methods of protection against such damage are possible and several of them are discussed in this paper. Laboratory experiments have been made to show the normal distribution under various steepnesses of waves, and the improvement of unsatisfactory distributions by means of condensers or lightning arresters connected to various parts of the windings has been studied.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124897001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538465
N. N. Smeloff, A. Price
The purpose of this paper is to describe the results of a lightning investigation conducted during 1928 and 1929 on 114 circuit miles of a 220-kv. system located in a territory where severe lightning storms are frequent. During the 1929 investigation, which was a continuation and expansion of previous years' work, a number of devices was successfully used, such as surge voltage recorders, cathode ray oscillographs, electric field intensity recorders, and lightning stroke recorders. Some of these devices are new. Many valuable data on magnitude and wave shape of actual lightning surges were obtained, proof of the existence of both single-and multiple-phase faults due to lightning; some data on the shielding effect of overhead ground wires, and qualitative data on the nature and lime of discharge of lightning strokes together with the atmospheric gradients resulting therefrom, were also obtained.
{"title":"Abridgment of lightning investigation on 220-kv. system of the Pennsylvania power & light company (1928 and 1929)","authors":"N. N. Smeloff, A. Price","doi":"10.1109/JAIEE.1930.6538465","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538465","url":null,"abstract":"The purpose of this paper is to describe the results of a lightning investigation conducted during 1928 and 1929 on 114 circuit miles of a 220-kv. system located in a territory where severe lightning storms are frequent. During the 1929 investigation, which was a continuation and expansion of previous years' work, a number of devices was successfully used, such as surge voltage recorders, cathode ray oscillographs, electric field intensity recorders, and lightning stroke recorders. Some of these devices are new. Many valuable data on magnitude and wave shape of actual lightning surges were obtained, proof of the existence of both single-and multiple-phase faults due to lightning; some data on the shielding effect of overhead ground wires, and qualitative data on the nature and lime of discharge of lightning strokes together with the atmospheric gradients resulting therefrom, were also obtained.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126384316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538470
W. J. Williams, R. G. Mccurdy
This paper describes a survey made to determine the range of magnitudes of room noise present in telephone locations. Measurements were made in a total of 260 locations in New York City and environs, distributed among businesses and residences in accordance with telephone traffic distribution. In each location, measurements were made by a marginal audibility method using the human ear as a part of the measuring device, and by a visual indicating meter. A brief description of the apparatus employed with each of these methods is included. Results presented for and measurements made in various classes of rooms, under winter and summer conditions.
{"title":"Abridgment a survey of room noise in telephone locations","authors":"W. J. Williams, R. G. Mccurdy","doi":"10.1109/JAIEE.1930.6538470","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538470","url":null,"abstract":"This paper describes a survey made to determine the range of magnitudes of room noise present in telephone locations. Measurements were made in a total of 260 locations in New York City and environs, distributed among businesses and residences in accordance with telephone traffic distribution. In each location, measurements were made by a marginal audibility method using the human ear as a part of the measuring device, and by a visual indicating meter. A brief description of the apparatus employed with each of these methods is included. Results presented for and measurements made in various classes of rooms, under winter and summer conditions.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125465352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538467
L. V. Bewley
The complete paper consists of three parts; I — Induced Potentials, II — Direct Hits, and III — Other Effects. The work of previous investigators is briefly reviewed, and the limitations of their premises pointed out. Under Part I, a generalized theory of ideal ground wires is offered, taking into account the law of cloud discharge, the distribution of bound charge, and the formation of traveling waves. It is found that the protective ratio is independent of these factors. A more extensive theory taking the additional factors of successive reflections and tower resistance into account is then developed. Part II discusses the probability of a line's being hit, and applies a method for computing the effect of successive reflections to the calculation of potentials on the line and ground wires. Curves of these potentials at successive towers and as functions of tower resistances and of time, are given. Part III discusses the effect of ground wires on attenuation, telephone interference, zero-phase sequence reactance, corona, and the reduction in surge impedance due to the introduction of extra ground wires. There are three mathematical appendixes. In Appendix I, Maxwell's electrostatic and electromagnetic coefficients are reviewed and the theory of traveling waves on any number of parallel wires, including the behavior of these waves at rather general transition points developed. While this extension to the theory of traveling waves was developed incidental to the study of ground wire theory, it is believed to be of considerable interest and value on its own account. Appendixes II and III are the mathematical analyses corresponding to Parts I and II, respectively.
{"title":"Abridgment of critique of ground wire theory","authors":"L. V. Bewley","doi":"10.1109/JAIEE.1930.6538467","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538467","url":null,"abstract":"The complete paper consists of three parts; I — Induced Potentials, II — Direct Hits, and III — Other Effects. The work of previous investigators is briefly reviewed, and the limitations of their premises pointed out. Under Part I, a generalized theory of ideal ground wires is offered, taking into account the law of cloud discharge, the distribution of bound charge, and the formation of traveling waves. It is found that the protective ratio is independent of these factors. A more extensive theory taking the additional factors of successive reflections and tower resistance into account is then developed. Part II discusses the probability of a line's being hit, and applies a method for computing the effect of successive reflections to the calculation of potentials on the line and ground wires. Curves of these potentials at successive towers and as functions of tower resistances and of time, are given. Part III discusses the effect of ground wires on attenuation, telephone interference, zero-phase sequence reactance, corona, and the reduction in surge impedance due to the introduction of extra ground wires. There are three mathematical appendixes. In Appendix I, Maxwell's electrostatic and electromagnetic coefficients are reviewed and the theory of traveling waves on any number of parallel wires, including the behavior of these waves at rather general transition points developed. While this extension to the theory of traveling waves was developed incidental to the study of ground wire theory, it is believed to be of considerable interest and value on its own account. Appendixes II and III are the mathematical analyses corresponding to Parts I and II, respectively.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"289 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121223352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538471
K. Hawley
Porcelain insulators have been manufactured and used for the transmission of high-voltage electric power for forty years. The first designs were of the single piece and multipart cemented pin type. Necessity of higher safety factors against flashover and increase in operating voltages demanded a rapid increase in the size of the insulators. This reached an economic limit at the operating voltage of 66 kv. The suspension unit overcame this temporary check of increased operating voltage. Further study of the electrostatic capacitance of the various parts and consequent voltage distribution, made marked refinements in the pin type insulator possible. During this time the single piece porcelain suspension unit took practically its present form. Early improvements were the provision of proper expansion joints and the separation of the lip of the cap from the porcelain hood. Gradual improvements have since been made resulting in a great increase in mechanical strength. These changes have been principally of hardware design. By experiment and analysis the shapes of the cap and pin have been determined to give a uniform distribution of load from the pin to the cap. Constant check tests by the quick pull and time loading methods have shown, that the suspension insulator with properly designed hardware and a suitable coating on the cap to prevent the cement from adhering to the metal, to have a high strength associated with electrical reliability. Ceramic research and exact manufacturing control has made possible the production of non-absorbent, thoroughly vitrified porcelain of consistent strength. This has centered largely about the proper firing of the clay. Recent experiments upon the properties of the combination of porcelain and glaze has eliminated surface stress and consequently assured stronger, longer lived porcelain. Still greater uniformity has been gained by glazing the sanded surfaces. The elimination of the abutting joint and the proper design of the cemented joint has stopped expansion troubles. Proper use of Portland cement has resulted in insulators able to withstand drastic temperature changes without harm. A recent improvement in the pin type insulator is the metal threaded pin hole. This has lessened manufacturing and construction difficulties and in addition due to the exact fit of the insulator on the pin, overcomes hidden corona and the consequent radio interference.
{"title":"Abridgment of development of the porcelain insulator","authors":"K. Hawley","doi":"10.1109/JAIEE.1930.6538471","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538471","url":null,"abstract":"Porcelain insulators have been manufactured and used for the transmission of high-voltage electric power for forty years. The first designs were of the single piece and multipart cemented pin type. Necessity of higher safety factors against flashover and increase in operating voltages demanded a rapid increase in the size of the insulators. This reached an economic limit at the operating voltage of 66 kv. The suspension unit overcame this temporary check of increased operating voltage. Further study of the electrostatic capacitance of the various parts and consequent voltage distribution, made marked refinements in the pin type insulator possible. During this time the single piece porcelain suspension unit took practically its present form. Early improvements were the provision of proper expansion joints and the separation of the lip of the cap from the porcelain hood. Gradual improvements have since been made resulting in a great increase in mechanical strength. These changes have been principally of hardware design. By experiment and analysis the shapes of the cap and pin have been determined to give a uniform distribution of load from the pin to the cap. Constant check tests by the quick pull and time loading methods have shown, that the suspension insulator with properly designed hardware and a suitable coating on the cap to prevent the cement from adhering to the metal, to have a high strength associated with electrical reliability. Ceramic research and exact manufacturing control has made possible the production of non-absorbent, thoroughly vitrified porcelain of consistent strength. This has centered largely about the proper firing of the clay. Recent experiments upon the properties of the combination of porcelain and glaze has eliminated surface stress and consequently assured stronger, longer lived porcelain. Still greater uniformity has been gained by glazing the sanded surfaces. The elimination of the abutting joint and the proper design of the cemented joint has stopped expansion troubles. Proper use of Portland cement has resulted in insulators able to withstand drastic temperature changes without harm. A recent improvement in the pin type insulator is the metal threaded pin hole. This has lessened manufacturing and construction difficulties and in addition due to the exact fit of the insulator on the pin, overcomes hidden corona and the consequent radio interference.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126986033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538461
C. E. Magnusson
This paper deals with new forms of Lichtenberg figures produced under the combined stress of dielectric and magnetic fields. The effects produced by the magnetic field may be used for determining whether electrons, positive ions, or protons, are basically the active elements in the formation of the positive as well as the negative figures. The illustrations also show that the presence of the magnetic field greatly extends the range of air pressures within which figures of definite form can be obtained, that figures taken at low air pressures possess structures strikingly different from those hitherto known, and that these figures may prove a key to the mechanism of the electric spark.
{"title":"Abridgment of effects of the magnetic field on Lichtenberg figures","authors":"C. E. Magnusson","doi":"10.1109/JAIEE.1930.6538461","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538461","url":null,"abstract":"This paper deals with new forms of Lichtenberg figures produced under the combined stress of dielectric and magnetic fields. The effects produced by the magnetic field may be used for determining whether electrons, positive ions, or protons, are basically the active elements in the formation of the positive as well as the negative figures. The illustrations also show that the presence of the magnetic field greatly extends the range of air pressures within which figures of definite form can be obtained, that figures taken at low air pressures possess structures strikingly different from those hitherto known, and that these figures may prove a key to the mechanism of the electric spark.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129708581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-09-01DOI: 10.1109/JAIEE.1930.6538462
K. B. Mceachron, J. G. Hemstreet, H. Seelye
Cathode ray oscillographic tests were made of traveling waves passing from an overhead line into short lengths of cable. Single-phase cable lengths of 500 and 1000 ft. were used. Tests were made with a wide variety of conditions, such as cable at end of line, cable between two sections of line, etc. The tests demonstrated that a short length of cable does not act as an effective protective device when connected between station and incoming line. When the incoming wave on the incoming line has a long flat top, several times the cable, length, the crest of the wave passing the cable is decreased only a few per cent by the presence of the cable, although the wave front is sloped off if it was originally very steep. When the wavelength is approximately the same as the cable length, the cable can reduce the transient voltage to less than half of the value without the cable. Recent measurements on transmission lines show that waves do occur with approximately flat tops which are several thousand feet in length. Therefore the cables do not permit the omission of lightning arresters which are means of reducing the potential of overvoltage surges. This confirms the theoretical calculations and the practise of using lightning arresters with cables. The resistance of the ground connection of the cable sheath was found to have important effects. With the cable sheath at the end grounded through 28 ohms, a potential of 82 kv. was measured at the sheath and 105 kv. at the cable conductor. The protective action of lightning arresters was demonstrated by using a gap and various values of series resistance. The velocity of propagation in the cable was found to be about 61 per cent of the velocity of light. The surge impedance of the cable was determined by several methods. Calculations based on the measured propagation velocity and measured capacitance gave a value of about 50 ohms. Some of the other methods gave values of about 100 ohms.
{"title":"Abridgment of study of the effect of short lengths of cable on traveling waves","authors":"K. B. Mceachron, J. G. Hemstreet, H. Seelye","doi":"10.1109/JAIEE.1930.6538462","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6538462","url":null,"abstract":"Cathode ray oscillographic tests were made of traveling waves passing from an overhead line into short lengths of cable. Single-phase cable lengths of 500 and 1000 ft. were used. Tests were made with a wide variety of conditions, such as cable at end of line, cable between two sections of line, etc. The tests demonstrated that a short length of cable does not act as an effective protective device when connected between station and incoming line. When the incoming wave on the incoming line has a long flat top, several times the cable, length, the crest of the wave passing the cable is decreased only a few per cent by the presence of the cable, although the wave front is sloped off if it was originally very steep. When the wavelength is approximately the same as the cable length, the cable can reduce the transient voltage to less than half of the value without the cable. Recent measurements on transmission lines show that waves do occur with approximately flat tops which are several thousand feet in length. Therefore the cables do not permit the omission of lightning arresters which are means of reducing the potential of overvoltage surges. This confirms the theoretical calculations and the practise of using lightning arresters with cables. The resistance of the ground connection of the cable sheath was found to have important effects. With the cable sheath at the end grounded through 28 ohms, a potential of 82 kv. was measured at the sheath and 105 kv. at the cable conductor. The protective action of lightning arresters was demonstrated by using a gap and various values of series resistance. The velocity of propagation in the cable was found to be about 61 per cent of the velocity of light. The surge impedance of the cable was determined by several methods. Calculations based on the measured propagation velocity and measured capacitance gave a value of about 50 ohms. Some of the other methods gave values of about 100 ohms.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116980749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1930-08-01DOI: 10.1109/JAIEE.1930.6535391
O. C. Traver, L. F. Kennedy
The usual methods of relaying are becoming inadequate for tie line application. The need for limiting the duration of faults on lines of major importance is unquestioned. The possibility of maintaining stability by quicker operation of protective equipment is well recognized. These considerations have resulted in the development of the high-speed relays and oil circuit breakers as steps in the over-all reduction of short-circuit duration.
{"title":"Abridgment of modern requirements for protective relays on important system interconnections","authors":"O. C. Traver, L. F. Kennedy","doi":"10.1109/JAIEE.1930.6535391","DOIUrl":"https://doi.org/10.1109/JAIEE.1930.6535391","url":null,"abstract":"The usual methods of relaying are becoming inadequate for tie line application. The need for limiting the duration of faults on lines of major importance is unquestioned. The possibility of maintaining stability by quicker operation of protective equipment is well recognized. These considerations have resulted in the development of the high-speed relays and oil circuit breakers as steps in the over-all reduction of short-circuit duration.","PeriodicalId":260406,"journal":{"name":"Journal of the A.I.E.E.","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1930-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116959045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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